1
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Zhang Z, Dong L, Tao H, Dong Y, Xiang W, Tao F, Zhao Y. RNA-binding proteins potentially regulate the alternative splicing of apoptotic genes during knee osteoarthritis progression. BMC Genomics 2024; 25:293. [PMID: 38504181 PMCID: PMC10949708 DOI: 10.1186/s12864-024-10181-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Accepted: 03/04/2024] [Indexed: 03/21/2024] Open
Abstract
BACKGROUND Alternative splicing (AS) is a principal mode of genetic regulation and one of the most widely used mechanisms to generate structurally and functionally distinct mRNA and protein variants. Dysregulation of AS may result in aberrant transcription and protein products, leading to the emergence of human diseases. Although considered important for regulating gene expression, genome-wide AS dysregulation, underlying mechanisms, and clinical relevance in knee osteoarthritis (OA) remain unelucidated. Therefore, in this study, we elucidated and validated AS events and their regulatory mechanisms during OA progression. RESULTS In this study, we identified differentially expressed genes between human OA and healthy meniscus samples. Among them, the OA-associated genes were primarily enriched in biological pathways such as extracellular matrix organization and ossification. The predominant OA-associated regulated AS (RAS) events were found to be involved in apoptosis during OA development. The expression of the apoptosis-related gene BCL2L13, XAF1, and NF2 were significantly different between OA and healthy meniscus samples. The construction of a covariation network of RNA-binding proteins (RBPs) and RAS genes revealed that differentially expressed RBP genes LAMA2 and CUL4B may regulate the apoptotic genes XAF1 and BCL2L13 to undergo AS events during OA progression. Finally, RT-qPCR revealed that CUL4B expression was significantly higher in OA meniscus samples than in normal controls and that the AS ratio of XAF1 was significantly different between control and OA samples; these findings were consistent with their expected expression and regulatory relationships. CONCLUSIONS Differentially expressed RBPs may regulate the AS of apoptotic genes during knee OA progression. XAF1 and its regulator, CUL4B, may serve as novel biomarkers and potential therapeutic targets for this disease.
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Affiliation(s)
- Zheng Zhang
- Department of Orthopedics, Renmin Hospital of Wuhan University, 238, Jiefang Road, Wuchang District, 430060, Wuhan, Hubei, China.
| | - Limei Dong
- School of Basic Medical Sciences, Wuhan University, 430071, Wuhan, Hubei, China
| | - Hai Tao
- Department of Orthopedics, Renmin Hospital of Wuhan University, 238, Jiefang Road, Wuchang District, 430060, Wuhan, Hubei, China
| | - Yusong Dong
- School of Basic Medical Sciences, Wuhan University, 430071, Wuhan, Hubei, China
| | - Wei Xiang
- Department of Orthopedics, Renmin Hospital of Wuhan University, 238, Jiefang Road, Wuchang District, 430060, Wuhan, Hubei, China
| | - Fenghua Tao
- Department of Orthopedics, Renmin Hospital of Wuhan University, 238, Jiefang Road, Wuchang District, 430060, Wuhan, Hubei, China
| | - Yingchun Zhao
- Department of Orthopedics, Renmin Hospital of Wuhan University, 238, Jiefang Road, Wuchang District, 430060, Wuhan, Hubei, China
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2
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Xiao C, M’Angale PG, Wang S, Lemieux A, Thomson T. Identifying new players in structural synaptic plasticity through dArc1 interrogation. iScience 2023; 26:108048. [PMID: 37876812 PMCID: PMC10590816 DOI: 10.1016/j.isci.2023.108048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Revised: 08/28/2023] [Accepted: 09/22/2023] [Indexed: 10/26/2023] Open
Abstract
The formation, expansion, and pruning of synapses, known as structural synaptic plasticity, is needed for learning and memory, and perturbation of plasticity is associated with many neurological disorders and diseases. Previously, we observed that the Drosophila homolog of Activity-regulated cytoskeleton-associated protein (dArc1), forms a capsid-like structure, associates with its own mRNA, and is transported across synapses. We demonstrated that this transfer is needed for structural synaptic plasticity. To identify mRNAs that are modified by dArc1 in presynaptic neuron and postsynaptic muscle, we disrupted the expression of dArc1 and performed genomic analysis with deep sequencing. We found that dArc1 affects the expression of genes involved in metabolism, phagocytosis, and RNA-splicing. Through immunoprecipitation we also identified potential mRNA cargos of dArc1 capsids. This study suggests that dArc1 acts as a master regulator of plasticity by affecting several distinct and highly conserved cellular processes.
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Affiliation(s)
- Cong Xiao
- Department of Neurobiology, University of Massachusetts Chan Medical School, 364 Plantation Street, Worcester, MA 01605, USA
| | - P. Githure M’Angale
- Department of Neurobiology, University of Massachusetts Chan Medical School, 364 Plantation Street, Worcester, MA 01605, USA
| | - Shuhao Wang
- Department of Neurobiology, University of Massachusetts Chan Medical School, 364 Plantation Street, Worcester, MA 01605, USA
| | - Adrienne Lemieux
- Department of Neurobiology, University of Massachusetts Chan Medical School, 364 Plantation Street, Worcester, MA 01605, USA
| | - Travis Thomson
- Department of Neurobiology, University of Massachusetts Chan Medical School, 364 Plantation Street, Worcester, MA 01605, USA
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3
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Ervilha Pereira P, Schuermans N, Meylemans A, LeBlanc P, Versluys L, Copley KE, Rubien JD, Altheimer C, Peetermans M, Debackere E, Vanakker O, Janssens S, Baets J, Verhoeven K, Lammens M, Symoens S, De Paepe B, Barmada SJ, Shorter J, De Bleecker JL, Bogaert E, Dermaut B. C-terminal frameshift variant of TDP-43 with pronounced aggregation-propensity causes rimmed vacuole myopathy but not ALS/FTD. Acta Neuropathol 2023; 145:793-814. [PMID: 37000196 PMCID: PMC10175433 DOI: 10.1007/s00401-023-02565-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 03/15/2023] [Accepted: 03/17/2023] [Indexed: 04/01/2023]
Abstract
Neuronal TDP-43-positive inclusions are neuropathological hallmark lesions in frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS). Pathogenic missense variants in TARDBP, the gene encoding TDP-43, can cause ALS and cluster in the C-terminal prion-like domain (PrLD), where they modulate the liquid condensation and aggregation properties of the protein. TDP-43-positive inclusions are also found in rimmed vacuole myopathies, including sporadic inclusion body myositis, but myopathy-causing TDP-43 variants have not been reported. Using genome-wide linkage analysis and whole exome sequencing in an extended five-generation family with an autosomal dominant rimmed vacuole myopathy, we identified a conclusively linked frameshift mutation in TDP-43 producing a C-terminally altered PrLD (TDP-43p.Trp385IlefsTer10) (maximum multipoint LOD-score 3.61). Patient-derived muscle biopsies showed TDP-43-positive sarcoplasmic inclusions, accumulation of autophagosomes and transcriptomes with abnormally spliced sarcomeric genes (including TTN and NEB) and increased expression of muscle regeneration genes. In vitro phase separation assays demonstrated that TDP-43Trp385IlefsTer10 does not form liquid-like condensates and readily forms solid-like fibrils indicating increased aggregation propensity compared to wild-type TDP-43. In Drosophila TDP-43p.Trp385IlefsTer10 behaved as a partial loss-of-function allele as it was able to rescue the TBPH (fly ortholog of TARDBP) neurodevelopmental lethal null phenotype while showing strongly reduced toxic gain-of-function properties upon overexpression. Accordingly, TDP-43p.Trp385IlefsTer10 showed reduced toxicity in a primary rat neuron disease model. Together, these genetic, pathological, in vitro and in vivo results demonstrate that TDP-43p.Trp385IlefsTer10 is an aggregation-prone partial loss-of-function variant that causes autosomal dominant vacuolar myopathy but not ALS/FTD. Our study genetically links TDP-43 proteinopathy to myodegeneration, and reveals a tissue-specific role of the PrLD in directing pathology.
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Affiliation(s)
- Pedro Ervilha Pereira
- Center for Medical Genetics, Ghent University Hospital, Ghent, Belgium
- Department of Biomolecular Medicine, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
| | - Nika Schuermans
- Center for Medical Genetics, Ghent University Hospital, Ghent, Belgium
- Department of Biomolecular Medicine, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
| | - Antoon Meylemans
- Department of Neurology, Ghent University Hospital, Ghent, Belgium
- Department of Head and Skin, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
| | - Pontus LeBlanc
- Center for Medical Genetics, Ghent University Hospital, Ghent, Belgium
- Department of Biomolecular Medicine, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
| | - Lauren Versluys
- Center for Medical Genetics, Ghent University Hospital, Ghent, Belgium
- Department of Biomolecular Medicine, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
| | - Katie E Copley
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
- Neuroscience Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Jack D Rubien
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | | | - Myra Peetermans
- Center for Medical Genetics, Ghent University Hospital, Ghent, Belgium
- Department of Biomolecular Medicine, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
| | - Elke Debackere
- Center for Medical Genetics, Ghent University Hospital, Ghent, Belgium
- Department of Biomolecular Medicine, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
| | - Olivier Vanakker
- Center for Medical Genetics, Ghent University Hospital, Ghent, Belgium
- Department of Biomolecular Medicine, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
| | - Sandra Janssens
- Center for Medical Genetics, Ghent University Hospital, Ghent, Belgium
- Department of Biomolecular Medicine, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
| | - Jonathan Baets
- Department of Neurology, Neuromuscular Reference Centre, Antwerp University Hospital, Antwerp, Belgium
- Faculty of Medicine and Health Sciences, Translational Neurosciences, University of Antwerp, Antwerp, Belgium
- Laboratory of Neuromuscular Pathology, Institute Born-Bunge, University of Antwerp, Antwerp, Belgium
| | - Kristof Verhoeven
- Department of Neurology, Ghent University Hospital, Ghent, Belgium
- Department of Neurology, Sint-Jan Hospital Bruges, Brugge, Belgium
| | - Martin Lammens
- Department of Pathology, Antwerp University Hospital, University of Antwerp, Edegem, Belgium
| | - Sofie Symoens
- Center for Medical Genetics, Ghent University Hospital, Ghent, Belgium
- Department of Biomolecular Medicine, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
| | - Boel De Paepe
- Department of Neurology, Ghent University Hospital, Ghent, Belgium
- Department of Head and Skin, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
| | - Sami J Barmada
- Department of Neurology, University of Michigan, Ann Arbor, MI, 48109, USA
| | - James Shorter
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
- Neuroscience Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Jan L De Bleecker
- Department of Neurology, Ghent University Hospital, Ghent, Belgium
- Department of Head and Skin, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
| | - Elke Bogaert
- Center for Medical Genetics, Ghent University Hospital, Ghent, Belgium.
- Department of Biomolecular Medicine, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium.
| | - Bart Dermaut
- Center for Medical Genetics, Ghent University Hospital, Ghent, Belgium.
- Department of Biomolecular Medicine, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium.
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4
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Rapisarda A, Bargiela A, Llamusi B, Pont I, Estrada-Tejedor R, Garcia-España E, Artero R, Perez-Alonso M. Defined D-hexapeptides bind CUG repeats and rescue phenotypes of myotonic dystrophy myotubes in a Drosophila model of the disease. Sci Rep 2021; 11:19417. [PMID: 34593893 PMCID: PMC8484449 DOI: 10.1038/s41598-021-98866-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Accepted: 09/14/2021] [Indexed: 11/17/2022] Open
Abstract
In Myotonic Dystrophy type 1 (DM1), a non-coding CTG repeats rare expansion disease; toxic double-stranded RNA hairpins sequester the RNA-binding proteins Muscleblind-like 1 and 2 (MBNL1 and 2) and trigger other DM1-related pathogenesis pathway defects. In this paper, we characterize four d-amino acid hexapeptides identified together with abp1, a peptide previously shown to stabilize CUG RNA in its single-stranded conformation. With the generalized sequence cpy(a/t)(q/w)e, these related peptides improved three MBNL-regulated exon inclusions in DM1-derived cells. Subsequent experiments showed that these compounds generally increased the relative expression of MBNL1 and its nuclear-cytoplasmic distribution, reduced hyperactivated autophagy, and increased the percentage of differentiated (Desmin-positive) cells in vitro. All peptides rescued atrophy of indirect flight muscles in a Drosophila model of the disease, and partially rescued muscle function according to climbing and flight tests. Investigation of their mechanism of action supports that all four compounds can bind to CUG repeats with slightly different association constant, but binding did not strongly influence the secondary structure of the toxic RNA in contrast to abp1. Finally, molecular modeling suggests a detailed view of the interactions of peptide-CUG RNA complexes useful in the chemical optimization of compounds.
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Affiliation(s)
- Anna Rapisarda
- Department of Genetics, University Institute for Biotechnology and Biomedicine (BIOTECMED), University of Valencia, Dr. Moliner, 50, 46100, Burjasot, Valencia, Spain.,Translational Genomics Group, INCLIVA Biomedical Research Institute, 46010, Valencia, Spain
| | - Ariadna Bargiela
- Department of Genetics, University Institute for Biotechnology and Biomedicine (BIOTECMED), University of Valencia, Dr. Moliner, 50, 46100, Burjasot, Valencia, Spain. .,Translational Genomics Group, INCLIVA Biomedical Research Institute, 46010, Valencia, Spain.
| | - Beatriz Llamusi
- Department of Genetics, University Institute for Biotechnology and Biomedicine (BIOTECMED), University of Valencia, Dr. Moliner, 50, 46100, Burjasot, Valencia, Spain.,Translational Genomics Group, INCLIVA Biomedical Research Institute, 46010, Valencia, Spain.,Arthex Biotech S.L. Catedrático Agustín Escardino 9, Parc Scientific University of Valencia, Paterna, Valencia, Spain
| | - Isabel Pont
- Instituto de Ciencia Molecular (ICMol), Departamento de Química Inorgánica, C. Catedrático José Beltrán 2, Universidad de Valencia, 46980, Paterna, Spain
| | | | - Enrique Garcia-España
- Instituto de Ciencia Molecular (ICMol), Departamento de Química Inorgánica, C. Catedrático José Beltrán 2, Universidad de Valencia, 46980, Paterna, Spain
| | - Ruben Artero
- Department of Genetics, University Institute for Biotechnology and Biomedicine (BIOTECMED), University of Valencia, Dr. Moliner, 50, 46100, Burjasot, Valencia, Spain.,Translational Genomics Group, INCLIVA Biomedical Research Institute, 46010, Valencia, Spain
| | - Manuel Perez-Alonso
- Department of Genetics, University Institute for Biotechnology and Biomedicine (BIOTECMED), University of Valencia, Dr. Moliner, 50, 46100, Burjasot, Valencia, Spain.,Translational Genomics Group, INCLIVA Biomedical Research Institute, 46010, Valencia, Spain
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5
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Blázquez-Bernal Á, Fernandez-Costa JM, Bargiela A, Artero R. Inhibition of autophagy rescues muscle atrophy in a LGMDD2 Drosophila model. FASEB J 2021; 35:e21914. [PMID: 34547132 DOI: 10.1096/fj.202100539rr] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 08/23/2021] [Accepted: 08/25/2021] [Indexed: 01/18/2023]
Abstract
Limb-girdle muscular dystrophy D2 (LGMDD2) is an ultrarare autosomal dominant myopathy caused by mutation of the normal stop codon of the TNPO3 nuclear importin. The mutant protein carries a 15 amino acid C-terminal extension associated with pathogenicity. Here we report the first animal model of the disease by expressing the human mutant TNPO3 gene in Drosophila musculature or motor neurons and concomitantly silencing the endogenous expression of the fly protein ortholog. A similar genotype expressing wildtype TNPO3 served as a control. Phenotypes characterization revealed that mutant TNPO3 expression targeted at muscles or motor neurons caused LGMDD2-like phenotypes such as muscle degeneration and atrophy, and reduced locomotor ability. Notably, LGMDD2 mutation increase TNPO3 at the transcript and protein level in the Drosophila model Upregulated muscle autophagy observed in LGMDD2 patients was also confirmed in the fly model, in which the anti-autophagic drug chloroquine was able to rescue histologic and functional phenotypes. Overall, we provide a proof of concept of autophagy as a target to treat disease phenotypes and propose a neurogenic component to explain mutant TNPO3 pathogenicity in diseased muscles.
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Affiliation(s)
- Águeda Blázquez-Bernal
- Translational Genomics Group, University Institute for Biotechnology and Biomedicine (BIOTECMED), University of Valencia, Valencia, Spain.,Area of Metabolism and Organic Failure, Incliva Health Research Institute, Valencia, Spain.,Incliva-CIPF Joint Unit, Valencia, Spain
| | - Juan M Fernandez-Costa
- Translational Genomics Group, University Institute for Biotechnology and Biomedicine (BIOTECMED), University of Valencia, Valencia, Spain.,Area of Metabolism and Organic Failure, Incliva Health Research Institute, Valencia, Spain.,Incliva-CIPF Joint Unit, Valencia, Spain
| | - Ariadna Bargiela
- Translational Genomics Group, University Institute for Biotechnology and Biomedicine (BIOTECMED), University of Valencia, Valencia, Spain.,Area of Metabolism and Organic Failure, Incliva Health Research Institute, Valencia, Spain.,Incliva-CIPF Joint Unit, Valencia, Spain
| | - Ruben Artero
- Translational Genomics Group, University Institute for Biotechnology and Biomedicine (BIOTECMED), University of Valencia, Valencia, Spain.,Area of Metabolism and Organic Failure, Incliva Health Research Institute, Valencia, Spain.,Incliva-CIPF Joint Unit, Valencia, Spain
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6
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Wall JM, Basu A, Zunica ERM, Dubuisson OS, Pergola K, Broussard JP, Kirwan JP, Axelrod CL, Johnson AE. CRISPR/Cas9-engineered Drosophila knock-in models to study VCP diseases. Dis Model Mech 2021; 14:dmm048603. [PMID: 34160014 PMCID: PMC8325010 DOI: 10.1242/dmm.048603] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2020] [Accepted: 06/11/2021] [Indexed: 01/08/2023] Open
Abstract
Mutations in Valosin Containing Protein (VCP) are associated with several degenerative diseases, including multisystem proteinopathy (MSP-1) and amyotrophic lateral sclerosis. However, patients with VCP mutations vary widely in their pathology and clinical penetrance, making it difficult to devise effective treatment strategies. A deeper understanding of how each mutation affects VCP function could enhance the prediction of clinical outcomes and design of personalized treatment options. The power of a genetically tractable model organism coupled with well-established in vivo assays and a relatively short life cycle make Drosophila an attractive system to study VCP disease pathogenesis. Using CRISPR/Cas9, we have generated individual Drosophila knock-in mutants that include nine hereditary VCP disease mutations. Our models display many hallmarks of VCP-mediated degeneration, including progressive decline in mobility, protein aggregate accumulation and defects in lysosomal and mitochondrial function. We also made some novel and unexpected findings, including nuclear morphology defects and sex-specific phenotypic differences in several mutants. Taken together, the Drosophila VCP disease models generated in this study will be useful for studying the etiology of individual VCP patient mutations and testing potential genetic and/or pharmacological therapies.
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Affiliation(s)
- Jordan M. Wall
- Louisiana State University, Department of Biological Sciences, Baton Rouge, LA 70803, USA
| | - Ankita Basu
- Louisiana State University, Department of Biological Sciences, Baton Rouge, LA 70803, USA
| | - Elizabeth R. M. Zunica
- Integrated Physiology and Molecular Medicine Laboratory, Pennington Biomedical Research Center, Baton Rouge, LA 70808, USA
| | - Olga S. Dubuisson
- Louisiana State University, Department of Biological Sciences, Baton Rouge, LA 70803, USA
| | - Kathryn Pergola
- Integrated Physiology and Molecular Medicine Laboratory, Pennington Biomedical Research Center, Baton Rouge, LA 70808, USA
- Department of Translational Services, Pennington Biomedical Research Center, Baton Rouge, LA 70808, USA
| | - Joshua P. Broussard
- Louisiana State University, Department of Biological Sciences, Baton Rouge, LA 70803, USA
| | - John P. Kirwan
- Integrated Physiology and Molecular Medicine Laboratory, Pennington Biomedical Research Center, Baton Rouge, LA 70808, USA
| | - Christopher L. Axelrod
- Integrated Physiology and Molecular Medicine Laboratory, Pennington Biomedical Research Center, Baton Rouge, LA 70808, USA
- Department of Translational Services, Pennington Biomedical Research Center, Baton Rouge, LA 70808, USA
| | - Alyssa E. Johnson
- Louisiana State University, Department of Biological Sciences, Baton Rouge, LA 70803, USA
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7
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Asakawa K, Handa H, Kawakami K. Multi-phaseted problems of TDP-43 in selective neuronal vulnerability in ALS. Cell Mol Life Sci 2021; 78:4453-4465. [PMID: 33709256 PMCID: PMC8195926 DOI: 10.1007/s00018-021-03792-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 02/03/2021] [Accepted: 02/18/2021] [Indexed: 10/28/2022]
Abstract
Transactive response DNA-binding protein 43 kDa (TDP-43) encoded by the TARDBP gene is an evolutionarily conserved heterogeneous nuclear ribonucleoprotein (hnRNP) that regulates multiple steps of RNA metabolism, and its cytoplasmic aggregation characterizes degenerating motor neurons in amyotrophic lateral sclerosis (ALS). In most ALS cases, cytoplasmic TDP-43 aggregation occurs in the absence of mutations in the coding sequence of TARDBP. Thus, a major challenge in ALS research is to understand the nature of pathological changes occurring in wild-type TDP-43 and to explore upstream events in intracellular and extracellular milieu that promote the pathological transition of TDP-43. Despite the inherent obstacles to analyzing TDP-43 dynamics in in vivo motor neurons due to their anatomical complexity and inaccessibility, recent studies using cellular and animal models have provided important mechanistic insights into potential links between TDP-43 and motor neuron vulnerability in ALS. This review is intended to provide an overview of the current literature on the function and regulation of TDP-43-containing RNP granules or membraneless organelles, as revealed by various models, and to discuss the potential mechanisms by which TDP-43 can cause selective vulnerability of motor neurons in ALS.
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Affiliation(s)
- Kazuhide Asakawa
- Department of Chemical Biology, Tokyo Medical University, Shinjuku-ku, Tokyo, 160-8402, Japan.
- Division of Molecular and Developmental Biology, National Institute of Genetics, 1111 Yata, Mishima, Shizuoka, 411-8540, Japan.
- Department of Genetics, Graduate University for Advanced Studies (SOKENDAI), 1111 Yata, Mishima, Shizuoka, 411-8540, Japan.
| | - Hiroshi Handa
- Department of Chemical Biology, Tokyo Medical University, Shinjuku-ku, Tokyo, 160-8402, Japan
| | - Koichi Kawakami
- Division of Molecular and Developmental Biology, National Institute of Genetics, 1111 Yata, Mishima, Shizuoka, 411-8540, Japan
- Department of Genetics, Graduate University for Advanced Studies (SOKENDAI), 1111 Yata, Mishima, Shizuoka, 411-8540, Japan
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8
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Layalle S, They L, Ourghani S, Raoul C, Soustelle L. Amyotrophic Lateral Sclerosis Genes in Drosophila melanogaster. Int J Mol Sci 2021; 22:ijms22020904. [PMID: 33477509 PMCID: PMC7831090 DOI: 10.3390/ijms22020904] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 01/13/2021] [Accepted: 01/14/2021] [Indexed: 12/11/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a devastating adult-onset neurodegenerative disease characterized by the progressive degeneration of upper and lower motoneurons. Most ALS cases are sporadic but approximately 10% of ALS cases are due to inherited mutations in identified genes. ALS-causing mutations were identified in over 30 genes with superoxide dismutase-1 (SOD1), chromosome 9 open reading frame 72 (C9orf72), fused in sarcoma (FUS), and TAR DNA-binding protein (TARDBP, encoding TDP-43) being the most frequent. In the last few decades, Drosophila melanogaster emerged as a versatile model for studying neurodegenerative diseases, including ALS. In this review, we describe the different Drosophila ALS models that have been successfully used to decipher the cellular and molecular pathways associated with SOD1, C9orf72, FUS, and TDP-43. The study of the known fruit fly orthologs of these ALS-related genes yielded significant insights into cellular mechanisms and physiological functions. Moreover, genetic screening in tissue-specific gain-of-function mutants that mimic ALS-associated phenotypes identified disease-modifying genes. Here, we propose a comprehensive review on the Drosophila research focused on four ALS-linked genes that has revealed novel pathogenic mechanisms and identified potential therapeutic targets for future therapy.
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Affiliation(s)
- Sophie Layalle
- The Neuroscience Institute of Montpellier, INSERM, University of Montpellier, 34091 Montpellier, France; (S.L.); (L.T.); (S.O.)
| | - Laetitia They
- The Neuroscience Institute of Montpellier, INSERM, University of Montpellier, 34091 Montpellier, France; (S.L.); (L.T.); (S.O.)
| | - Sarah Ourghani
- The Neuroscience Institute of Montpellier, INSERM, University of Montpellier, 34091 Montpellier, France; (S.L.); (L.T.); (S.O.)
| | - Cédric Raoul
- The Neuroscience Institute of Montpellier, INSERM, University of Montpellier, 34091 Montpellier, France; (S.L.); (L.T.); (S.O.)
- Laboratory of Neurobiology, Kazan Federal University, 420008 Kazan, Russia
- Correspondence: (C.R.); (L.S.)
| | - Laurent Soustelle
- The Neuroscience Institute of Montpellier, INSERM, University of Montpellier, 34091 Montpellier, France; (S.L.); (L.T.); (S.O.)
- Correspondence: (C.R.); (L.S.)
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9
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Ozimski LL, Sabater-Arcis M, Bargiela A, Artero R. The hallmarks of myotonic dystrophy type 1 muscle dysfunction. Biol Rev Camb Philos Soc 2020; 96:716-730. [PMID: 33269537 DOI: 10.1111/brv.12674] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 11/18/2020] [Accepted: 11/20/2020] [Indexed: 12/20/2022]
Abstract
Myotonic dystrophy type 1 (DM1) is the most prevalent form of muscular dystrophy in adults and yet there are currently no treatment options. Although this disease causes multisystemic symptoms, it is mainly characterised by myopathy or diseased muscles, which includes muscle weakness, atrophy, and myotonia, severely affecting the lives of patients worldwide. On a molecular level, DM1 is caused by an expansion of CTG repeats in the 3' untranslated region (3'UTR) of the DM1 Protein Kinase (DMPK) gene which become pathogenic when transcribed into RNA forming ribonuclear foci comprised of auto complementary CUG hairpin structures that can bind proteins. This leads to the sequestration of the muscleblind-like (MBNL) family of proteins, depleting them, and the abnormal stabilisation of CUGBP Elav-like family member 1 (CELF1), enhancing it. Traditionally, DM1 research has focused on this RNA toxicity and how it alters MBNL and CELF1 functions as key splicing regulators. However, other proteins are affected by the toxic DMPK RNA and there is strong evidence that supports various signalling cascades playing an important role in DM1 pathogenesis. Specifically, the impairment of protein kinase B (AKT) signalling in DM1 increases autophagy, apoptosis, and ubiquitin-proteasome activity, which may also be affected in DM1 by AMP-activated protein kinase (AMPK) downregulation. AKT also regulates CELF1 directly, by affecting its subcellular localisation, and indirectly as it inhibits glycogen synthase kinase 3 beta (GSK3β), which stabilises the repressive form of CELF1 in DM1. Another kinase that contributes to CELF1 mis-regulation, in this case by hyperphosphorylation, is protein kinase C (PKC). Additionally, it has been demonstrated that fibroblast growth factor-inducible 14 (Fn14) is induced in DM1 and is associated with downstream signalling through the nuclear factor κB (NFκB) pathways, associating inflammation with this disease. Furthermore, MBNL1 and CELF1 play a role in cytoplasmic processes involved in DM1 myopathy, altering proteostasis and sarcomere structure. Finally, there are many other elements that could contribute to the muscular phenotype in DM1 such as alterations to satellite cells, non-coding RNA metabolism, calcium dysregulation, and repeat-associated non-ATG (RAN) translation. This review aims to organise the currently dispersed knowledge on the different pathways affected in DM1 and discusses the unexplored connections that could potentially help in providing new therapeutic targets in DM1 research.
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Affiliation(s)
- Lauren L Ozimski
- Translational Genomics Group, Incliva Health Research Institute, Avda. Menéndez Pelayo 4 acc., Valencia, 46010, Spain.,University Institute for Biotechnology and Biomedicine, Dr. Moliner 50, Burjasot, Valencia, 46100, Spain.,CIPF-INCLIVA Joint Unit, Valencia, 46012, Spain.,Arthex Biotech, Catedrático Escardino, 9, Paterna, Valencia, 46980, Spain
| | - Maria Sabater-Arcis
- Translational Genomics Group, Incliva Health Research Institute, Avda. Menéndez Pelayo 4 acc., Valencia, 46010, Spain.,University Institute for Biotechnology and Biomedicine, Dr. Moliner 50, Burjasot, Valencia, 46100, Spain.,CIPF-INCLIVA Joint Unit, Valencia, 46012, Spain
| | - Ariadna Bargiela
- Translational Genomics Group, Incliva Health Research Institute, Avda. Menéndez Pelayo 4 acc., Valencia, 46010, Spain.,University Institute for Biotechnology and Biomedicine, Dr. Moliner 50, Burjasot, Valencia, 46100, Spain.,CIPF-INCLIVA Joint Unit, Valencia, 46012, Spain
| | - Ruben Artero
- Translational Genomics Group, Incliva Health Research Institute, Avda. Menéndez Pelayo 4 acc., Valencia, 46010, Spain.,University Institute for Biotechnology and Biomedicine, Dr. Moliner 50, Burjasot, Valencia, 46100, Spain.,CIPF-INCLIVA Joint Unit, Valencia, 46012, Spain
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10
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Yadava RS, Yu Q, Mandal M, Rigo F, Bennett CF, Mahadevan MS. Systemic therapy in an RNA toxicity mouse model with an antisense oligonucleotide therapy targeting a non-CUG sequence within the DMPK 3'UTR RNA. Hum Mol Genet 2020; 29:1440-1453. [PMID: 32242217 PMCID: PMC7268549 DOI: 10.1093/hmg/ddaa060] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Revised: 03/19/2020] [Accepted: 03/30/2020] [Indexed: 12/17/2022] Open
Abstract
Myotonic dystrophy type 1 (DM1), the most common adult muscular dystrophy, is an autosomal dominant disorder caused by an expansion of a (CTG)n tract within the 3' untranslated region (3'UTR) of the dystrophia myotonica protein kinase (DMPK) gene. Mutant DMPK mRNAs are toxic, present in nuclear RNA foci and correlated with a plethora of RNA splicing defects. Cardinal features of DM1 are myotonia and cardiac conduction abnormalities. Using transgenic mice, we have demonstrated that expression of the mutant DMPK 3'UTR is sufficient to elicit these features of DM1. Here, using these mice, we present a study of systemic treatment with an antisense oligonucleotide (ASO) (ISIS 486178) targeted to a non-CUG sequence within the 3'UTR of DMPK. RNA foci and DMPK 3'UTR mRNA levels were reduced in both the heart and skeletal muscles. This correlated with improvements in several splicing defects in skeletal and cardiac muscles. The treatment reduced myotonia and this correlated with increased Clcn1 expression. Furthermore, functional testing showed improvements in treadmill running. Of note, we demonstrate that the ASO treatment reversed the cardiac conduction abnormalities, and this correlated with restoration of Gja5 (connexin 40) expression in the heart. This is the first time that an ASO targeting a non-CUG sequence within the DMPK 3'UTR has demonstrated benefit on the key DM1 phenotypes of myotonia and cardiac conduction defects. Our data also shows for the first time that ASOs may be a viable option for treating cardiac pathology in DM1.
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Affiliation(s)
- Ramesh S Yadava
- Department of Pathology, University of Virginia, Charlottesville, VA 22908, USA
| | - Qing Yu
- Department of Pathology, University of Virginia, Charlottesville, VA 22908, USA
| | - Mahua Mandal
- Department of Pathology, University of Virginia, Charlottesville, VA 22908, USA
| | - Frank Rigo
- Ionis Pharmaceuticals Inc., Carlsbad, CA 90210, USA
| | | | - Mani S Mahadevan
- Department of Pathology, University of Virginia, Charlottesville, VA 22908, USA
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11
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Sidisky JM, Babcock DT. Visualizing Synaptic Degeneration in Adult Drosophila in Association with Neurodegeneration. J Vis Exp 2020. [PMID: 32478750 DOI: 10.3791/61363] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Drosophila serves as a useful model for assessing synaptic structure and function associated with neurodegenerative diseases. While much work has focused on neuromuscular junctions (NMJs) in Drosophila larvae, assessing synaptic integrity in adult Drosophila has received much less attention. Here we provide a straightforward method for dissection of the dorsal longitudinal muscles (DLMs), which are required for flight ability. In addition to flight as a behavioral readout, this dissection allows for the both DLM synapses and muscle tissue to be amenable to structural analysis using fluorescently labeled antibodies for synaptic markers or proteins of interest. This protocol allows for the evaluation of the structural integrity of synapses in adult Drosophila during aging to model the progressive, age-dependent nature of most neurodegenerative diseases.
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12
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Strah N, Romano G, Introna C, Klima R, Marzullo M, Ciapponi L, Megighian A, Nizzardo M, Feiguin F. TDP-43 promotes the formation of neuromuscular synapses through the regulation of Disc-large expression in Drosophila skeletal muscles. BMC Biol 2020; 18:34. [PMID: 32216790 PMCID: PMC7099817 DOI: 10.1186/s12915-020-00767-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Accepted: 03/10/2020] [Indexed: 12/12/2022] Open
Abstract
Background The ribonuclear protein TDP-43 has been implicated in the pathophysiology of amyotrophic lateral sclerosis (ALS), with genetic mutations being linked to the neurological symptoms of the disease. Though alterations in the intracellular distribution of TDP-43 have been observed in skeletal muscles of patients suffering from ALS, it is not clear whether such modifications play an active role in the disease or merely represent an expression of muscle homeostatic mechanisms. Also, the molecular and metabolic pathways regulated by TDP-43 in the skeletal muscle remain largely unknown. Here, we analyze the function of TBPH, the Drosophila melanogaster ortholog of TDP-43, in skeletal muscles. Results We modulated the activity of TDP-43 in Drosophila muscles by means of RNA interference and observed that it is required to promote the formation and growth of neuromuscular synapses. TDP-43 regulated the expression levels of Disc-large (Dlg), and restoring Dlg expression either in skeletal muscles or in motoneurons was sufficient to suppress the locomotive and synaptic defects of TDP-43-null flies. These results were validated by the observation of a decrease in Dlg levels in human neuroblastoma cells and iPSC-differentiated motoneurons derived from ALS patients, suggesting similar mechanisms may potentially be involved in the pathophysiology of the disease. Conclusions Our results help to unveil the physiological role of TDP-43 in skeletal muscles as well as the mechanisms responsible for the autonomous and non-autonomous behavior of this protein concerning the organization of neuromuscular synapses.
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Affiliation(s)
- Nina Strah
- International Centre for Genetic Engineering and Biotechnology, Padriciano 99, 34149, Trieste, Italy
| | - Giulia Romano
- International Centre for Genetic Engineering and Biotechnology, Padriciano 99, 34149, Trieste, Italy
| | - Clelia Introna
- International Centre for Genetic Engineering and Biotechnology, Padriciano 99, 34149, Trieste, Italy
| | - Raffaella Klima
- International Centre for Genetic Engineering and Biotechnology, Padriciano 99, 34149, Trieste, Italy
| | - Marta Marzullo
- Istituto di Biologia e Patologia Molecolari del CNR, Sapienza Università di Roma, Rome, Italy.,Dipartimento di Biologia e Biotecnologie "C. Darwin", Sapienza Università di Roma, Rome, Italy
| | - Laura Ciapponi
- Dipartimento di Biologia e Biotecnologie "C. Darwin", Sapienza Università di Roma, Rome, Italy
| | - Aram Megighian
- Department of Biomedical Sciences, University of Padova, via Marzolo 3, 35131, Padua, Italy
| | - Monica Nizzardo
- Department of Pathophysiology and Transplantation (DePT), Dino Ferrari Centre, University of Milan, Neuroscience Section, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Via Francesco Sforza 35, 20122, Milan, Italy
| | - Fabian Feiguin
- International Centre for Genetic Engineering and Biotechnology, Padriciano 99, 34149, Trieste, Italy.
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13
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Increased Muscleblind levels by chloroquine treatment improve myotonic dystrophy type 1 phenotypes in in vitro and in vivo models. Proc Natl Acad Sci U S A 2019; 116:25203-25213. [PMID: 31754023 DOI: 10.1073/pnas.1820297116] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Myotonic dystrophy type 1 (DM1) is a life-threatening and chronically debilitating neuromuscular disease caused by the expansion of a CTG trinucleotide repeat in the 3' UTR of the DMPK gene. The mutant RNA forms insoluble structures capable of sequestering RNA binding proteins of the Muscleblind-like (MBNL) family, which ultimately leads to phenotypes. In this work, we demonstrate that treatment with the antiautophagic drug chloroquine was sufficient to up-regulate MBNL1 and 2 proteins in Drosophila and mouse (HSALR) models and patient-derived myoblasts. Extra Muscleblind was functional at the molecular level and improved splicing events regulated by MBNLs in all disease models. In vivo, chloroquine restored locomotion, rescued average cross-sectional muscle area, and extended median survival in DM1 flies. In HSALR mice, the drug restored muscular strength and histopathology signs and reduced the grade of myotonia. Taken together, these results offer a means to replenish critically low MBNL levels in DM1.
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14
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Nikonova E, Kao SY, Ravichandran K, Wittner A, Spletter ML. Conserved functions of RNA-binding proteins in muscle. Int J Biochem Cell Biol 2019; 110:29-49. [PMID: 30818081 DOI: 10.1016/j.biocel.2019.02.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2018] [Revised: 02/21/2019] [Accepted: 02/23/2019] [Indexed: 12/13/2022]
Abstract
Animals require different types of muscle for survival, for example for circulation, motility, reproduction and digestion. Much emphasis in the muscle field has been placed on understanding how transcriptional regulation generates diverse types of muscle during development. Recent work indicates that alternative splicing and RNA regulation are as critical to muscle development, and altered function of RNA-binding proteins causes muscle disease. Although hundreds of genes predicted to bind RNA are expressed in muscles, many fewer have been functionally characterized. We present a cross-species view summarizing what is known about RNA-binding protein function in muscle, from worms and flies to zebrafish, mice and humans. In particular, we focus on alternative splicing regulated by the CELF, MBNL and RBFOX families of proteins. We discuss the systemic nature of diseases associated with loss of RNA-binding proteins in muscle, focusing on mis-regulation of CELF and MBNL in myotonic dystrophy. These examples illustrate the conservation of RNA-binding protein function and the marked utility of genetic model systems in understanding mechanisms of RNA regulation.
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Affiliation(s)
- Elena Nikonova
- Biomedical Center, Department of Physiological Chemistry, Ludwig-Maximilians-University München, Großhaderner Str. 9, 82152, Martinsried-Planegg, Germany
| | - Shao-Yen Kao
- Biomedical Center, Department of Physiological Chemistry, Ludwig-Maximilians-University München, Großhaderner Str. 9, 82152, Martinsried-Planegg, Germany
| | - Keshika Ravichandran
- Biomedical Center, Department of Physiological Chemistry, Ludwig-Maximilians-University München, Großhaderner Str. 9, 82152, Martinsried-Planegg, Germany
| | - Anja Wittner
- Biomedical Center, Department of Physiological Chemistry, Ludwig-Maximilians-University München, Großhaderner Str. 9, 82152, Martinsried-Planegg, Germany
| | - Maria L Spletter
- Biomedical Center, Department of Physiological Chemistry, Ludwig-Maximilians-University München, Großhaderner Str. 9, 82152, Martinsried-Planegg, Germany; Center for Integrated Protein Science Munich (CIPSM) at the Department of Chemistry, Ludwig-Maximilians-Universität München, Munich, Germany.
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15
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TDP-43 and RNA form amyloid-like myo-granules in regenerating muscle. Nature 2018; 563:508-513. [PMID: 30464263 PMCID: PMC6324568 DOI: 10.1038/s41586-018-0665-2] [Citation(s) in RCA: 139] [Impact Index Per Article: 23.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2018] [Accepted: 10/03/2018] [Indexed: 12/17/2022]
Abstract
A dominant histopathological feature in neuromuscular diseases, including amyotrophic lateral sclerosis and inclusion body myopathy, is cytoplasmic aggregation of the RNA-binding protein TDP-43. Although rare mutations in TARDBP-the gene that encodes TDP-43-that lead to protein misfolding often cause protein aggregation, most patients do not have any mutations in TARDBP. Therefore, aggregates of wild-type TDP-43 arise in most patients by an unknown mechanism. Here we show that TDP-43 is an essential protein for normal skeletal muscle formation that unexpectedly forms cytoplasmic, amyloid-like oligomeric assemblies, which we call myo-granules, during regeneration of skeletal muscle in mice and humans. Myo-granules bind to mRNAs that encode sarcomeric proteins and are cleared as myofibres mature. Although myo-granules occur during normal skeletal-muscle regeneration, myo-granules can seed TDP-43 amyloid fibrils in vitro and are increased in a mouse model of inclusion body myopathy. Therefore, increased assembly or decreased clearance of functionally normal myo-granules could be the source of cytoplasmic TDP-43 aggregates that commonly occur in neuromuscular disease.
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16
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Picchio L, Legagneux V, Deschamps S, Renaud Y, Chauveau S, Paillard L, Jagla K. Bruno-3 regulates sarcomere component expression and contributes to muscle phenotypes of myotonic dystrophy type 1. Dis Model Mech 2018; 11:dmm.031849. [PMID: 29716962 PMCID: PMC5992612 DOI: 10.1242/dmm.031849] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Accepted: 04/18/2018] [Indexed: 01/22/2023] Open
Abstract
Steinert disease, or myotonic dystrophy type 1 (DM1), is a multisystemic disorder caused by toxic noncoding CUG repeat transcripts, leading to altered levels of two RNA binding factors, MBNL1 and CELF1. The contribution of CELF1 to DM1 phenotypes is controversial. Here, we show that the Drosophila CELF1 family member, Bru-3, contributes to pathogenic muscle defects observed in a Drosophila model of DM1. Bru-3 displays predominantly cytoplasmic expression in muscles and its muscle-specific overexpression causes a range of phenotypes also observed in the fly DM1 model, including affected motility, fiber splitting, reduced myofiber length and altered myoblast fusion. Interestingly, comparative genome-wide transcriptomic analyses revealed that Bru-3 negatively regulates levels of mRNAs encoding a set of sarcomere components, including Actn transcripts. Conversely, it acts as a positive regulator of Actn translation. As CELF1 displays predominantly cytoplasmic expression in differentiating C2C12 myotubes and binds to Actn mRNA, we hypothesize that it might exert analogous functions in vertebrate muscles. Altogether, we propose that cytoplasmic Bru-3 contributes to DM1 pathogenesis in a Drosophila model by regulating sarcomeric transcripts and protein levels.
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Affiliation(s)
- Lucie Picchio
- GReD (Genetics, Reproduction and Development Laboratory), INSERM 1103, CNRS 6293, University of Clermont Auvergne, 28 Place Henri Dunant, 63000 Clermont-Ferrand, France
| | - Vincent Legagneux
- IGDR (Institut de Génétique et Développement de Rennes), UMR 6290 CNRS, Université de Rennes, 2 Avenue Léon Bernard, 35000 Rennes, France.,Inserm UMR1085 IRSET, Université de Rennes 1, 35000 Rennes, France.,CNRS-Université de Rennes1-INRIA, UMR6074 IRISA, 35000 Rennes, France
| | - Stephane Deschamps
- IGDR (Institut de Génétique et Développement de Rennes), UMR 6290 CNRS, Université de Rennes, 2 Avenue Léon Bernard, 35000 Rennes, France
| | - Yoan Renaud
- GReD (Genetics, Reproduction and Development Laboratory), INSERM 1103, CNRS 6293, University of Clermont Auvergne, 28 Place Henri Dunant, 63000 Clermont-Ferrand, France
| | - Sabine Chauveau
- GReD (Genetics, Reproduction and Development Laboratory), INSERM 1103, CNRS 6293, University of Clermont Auvergne, 28 Place Henri Dunant, 63000 Clermont-Ferrand, France
| | - Luc Paillard
- IGDR (Institut de Génétique et Développement de Rennes), UMR 6290 CNRS, Université de Rennes, 2 Avenue Léon Bernard, 35000 Rennes, France
| | - Krzysztof Jagla
- GReD (Genetics, Reproduction and Development Laboratory), INSERM 1103, CNRS 6293, University of Clermont Auvergne, 28 Place Henri Dunant, 63000 Clermont-Ferrand, France
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17
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Chakraborty M, Sellier C, Ney M, Pascal V, Charlet-Berguerand N, Artero R, Llamusi B. Daunorubicin reduces MBNL1 sequestration caused by CUG-repeat expansion and rescues cardiac dysfunctions in a Drosophila model of myotonic dystrophy. Dis Model Mech 2018; 11:dmm.032557. [PMID: 29592894 PMCID: PMC5963859 DOI: 10.1242/dmm.032557] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Accepted: 03/14/2018] [Indexed: 01/09/2023] Open
Abstract
Myotonic dystrophy (DM) is a dominantly inherited neuromuscular disorder caused by expression of mutant myotonin-protein kinase (DMPK) transcripts containing expanded CUG repeats. Pathogenic DMPK RNA sequesters the muscleblind-like (MBNL) proteins, causing alterations in metabolism of various RNAs. Cardiac dysfunction represents the second most common cause of death in DM type 1 (DM1) patients. However, the contribution of MBNL sequestration in DM1 cardiac dysfunction is unclear. We overexpressed Muscleblind (Mbl), the DrosophilaMBNL orthologue, in cardiomyocytes of DM1 model flies and observed a rescue of heart dysfunctions, which are characteristic of these model flies and resemble cardiac defects observed in patients. We also identified a drug – daunorubicin hydrochloride – that directly binds to CUG repeats and alleviates Mbl sequestration in Drosophila DM1 cardiomyocytes, resulting in mis-splicing rescue and cardiac function recovery. These results demonstrate the relevance of Mbl sequestration caused by expanded-CUG-repeat RNA in cardiac dysfunctions in DM1, and highlight the potential of strategies aimed at inhibiting this protein-RNA interaction to recover normal cardiac function. Summary: MBNL protein sequestration by expanded CUG RNA contributes towards cardiac dysfunction in a myotonic dystrophy Drosophila model. Here, the authors identify the anticancer drug daunorubicin as a candidate therapeutic for the disease.
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Affiliation(s)
- Mouli Chakraborty
- Translational Genomics Group, Incliva Health Research Institute, Valencia, Spain.,Department of Genetics and Interdisciplinary Research Structure for Biotechnology and Biomedicine (ERI BIOTECMED), University of Valencia, Valencia 46100, Spain.,CIPF-INCLIVA Joint Unit, Valencia 46100, Spain
| | - Chantal Sellier
- Translational Medicine and Neurogenetics, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U964, CNRS UMR7104, University of Strasbourg, 1 Rue Laurent Fries, 67400 Illkirch-Graffenstaden, France
| | - Michel Ney
- Translational Medicine and Neurogenetics, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U964, CNRS UMR7104, University of Strasbourg, 1 Rue Laurent Fries, 67400 Illkirch-Graffenstaden, France
| | - Villa Pascal
- PCBIS Plate-forme de Chimie Biologique Intégrative de Strasbourg CNRS UMS 3286, Labex Medalis, ESBS, Université de Strasbourg, 300 Boulevard Sébastien Brant, 67412 Illkirch, France
| | - Nicolas Charlet-Berguerand
- Translational Medicine and Neurogenetics, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U964, CNRS UMR7104, University of Strasbourg, 1 Rue Laurent Fries, 67400 Illkirch-Graffenstaden, France
| | - Ruben Artero
- Translational Genomics Group, Incliva Health Research Institute, Valencia, Spain .,Department of Genetics and Interdisciplinary Research Structure for Biotechnology and Biomedicine (ERI BIOTECMED), University of Valencia, Valencia 46100, Spain.,CIPF-INCLIVA Joint Unit, Valencia 46100, Spain
| | - Beatriz Llamusi
- Translational Genomics Group, Incliva Health Research Institute, Valencia, Spain.,Department of Genetics and Interdisciplinary Research Structure for Biotechnology and Biomedicine (ERI BIOTECMED), University of Valencia, Valencia 46100, Spain.,CIPF-INCLIVA Joint Unit, Valencia 46100, Spain
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18
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Selma-Soriano E, Artero R, Llamusi B. Optical Cross-Sectional Muscle Area Determination of Drosophila Melanogaster Adult Indirect Flight Muscles. J Vis Exp 2018. [PMID: 29658931 DOI: 10.3791/56179] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Muscle mass wasting, known as muscle atrophy, is a common phenotype in Drosophila models of neuromuscular diseases. We have used the indirect flight muscles (IFMs) of flies, specifically the dorso-longitudinal muscles (DLM), as the experimental subject to measure the atrophic phenotype brought about by different genetic causes. In this protocol, we describe how to embed fly thorax muscles for semi thin sectioning, how to obtain a good contrast between muscle and the surrounding tissue, and how to process optical microscope images for semiautomatic acquisition of quantifiable data and analysis. We describe three specific applications of the methodological pipeline. First, we show how the method can be applied to quantify muscle degeneration in a myotonic dystrophy fly model; second, measurement of muscle cross-sectional area can help to identify genes that either promote or prevent muscle atrophy and/or muscle degeneration; third, this protocol can be applied to determine whether a candidate compound is able to significantly modify a given atrophic phenotype induced by a disease-causing mutation or by an environmental trigger.
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Affiliation(s)
- Estela Selma-Soriano
- Department of Genetics and Interdisciplinary Research Structure for Biotechnology and Biomedicine (BIOTECMED), University of Valencia; Incliva Health Research Institute; Joint unit CIPF-Incliva
| | - Rubén Artero
- Department of Genetics and Interdisciplinary Research Structure for Biotechnology and Biomedicine (BIOTECMED), University of Valencia; Incliva Health Research Institute; Joint unit CIPF-Incliva;
| | - Beatriz Llamusi
- Department of Genetics and Interdisciplinary Research Structure for Biotechnology and Biomedicine (BIOTECMED), University of Valencia; Incliva Health Research Institute; Joint unit CIPF-Incliva
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19
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Expanded CCUG repeat RNA expression in Drosophila heart and muscle trigger Myotonic Dystrophy type 1-like phenotypes and activate autophagocytosis genes. Sci Rep 2017; 7:2843. [PMID: 28588248 PMCID: PMC5460254 DOI: 10.1038/s41598-017-02829-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Accepted: 04/19/2017] [Indexed: 12/12/2022] Open
Abstract
Myotonic dystrophies (DM1–2) are neuromuscular genetic disorders caused by the pathological expansion of untranslated microsatellites. DM1 and DM2, are caused by expanded CTG repeats in the 3′UTR of the DMPK gene and CCTG repeats in the first intron of the CNBP gene, respectively. Mutant RNAs containing expanded repeats are retained in the cell nucleus, where they sequester nuclear factors and cause alterations in RNA metabolism. However, for unknown reasons, DM1 is more severe than DM2. To study the differences and similarities in the pathogenesis of DM1 and DM2, we generated model flies by expressing pure expanded CUG ([250]×) or CCUG ([1100]×) repeats, respectively, and compared them with control flies expressing either 20 repeat units or GFP. We observed surprisingly severe muscle reduction and cardiac dysfunction in CCUG-expressing model flies. The muscle and cardiac tissue of both DM1 and DM2 model flies showed DM1-like phenotypes including overexpression of autophagy-related genes, RNA mis-splicing and repeat RNA aggregation in ribonuclear foci along with the Muscleblind protein. These data reveal, for the first time, that expanded non-coding CCUG repeat-RNA has similar in vivo toxicity potential as expanded CUG RNA in muscle and heart tissues and suggests that specific, as yet unknown factors, quench CCUG-repeat toxicity in DM2 patients.
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20
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Jagla K, Kalman B, Boudou T, Hénon S, Batonnet-Pichon S. Beyond mice: Emerging and transdisciplinary models for the study of early-onset myopathies. Semin Cell Dev Biol 2017; 64:171-180. [DOI: 10.1016/j.semcdb.2016.09.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Revised: 09/06/2016] [Accepted: 09/22/2016] [Indexed: 01/23/2023]
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21
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Derepressing muscleblind expression by miRNA sponges ameliorates myotonic dystrophy-like phenotypes in Drosophila. Sci Rep 2016; 6:36230. [PMID: 27805016 PMCID: PMC5090246 DOI: 10.1038/srep36230] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Accepted: 10/12/2016] [Indexed: 02/06/2023] Open
Abstract
Myotonic Dystrophy type 1 (DM1) originates from alleles of the DMPK gene with hundreds of extra CTG repeats in the 3′ untranslated region (3′ UTR). CUG repeat RNAs accumulate in foci that sequester Muscleblind-like (MBNL) proteins away from their functional target transcripts. Endogenous upregulation of MBNL proteins is, thus, a potential therapeutic approach to DM1. Here we identify two miRNAs, dme-miR-277 and dme-miR-304, that differentially regulate muscleblind RNA isoforms in miRNA sensor constructs. We also show that their sequestration by sponge constructs derepresses endogenous muscleblind not only in a wild type background but also in a DM1 Drosophila model expressing non-coding CUG trinucleotide repeats throughout the musculature. Enhanced muscleblind expression resulted in significant rescue of pathological phenotypes, including reversal of several mis-splicing events and reduced muscle atrophy in DM1 adult flies. Rescued flies had improved muscle function in climbing and flight assays, and had longer lifespan compared to disease controls. These studies provide proof of concept for a similar potentially therapeutic approach to DM1 in humans.
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Bondy-Chorney E, Crawford Parks TE, Ravel-Chapuis A, Jasmin BJ, Côté J. Staufen1s role as a splicing factor and a disease modifier in Myotonic Dystrophy Type I. Rare Dis 2016; 4:e1225644. [PMID: 27695661 PMCID: PMC5027583 DOI: 10.1080/21675511.2016.1225644] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Revised: 06/23/2016] [Accepted: 08/11/2016] [Indexed: 12/19/2022] Open
Abstract
In a recent issue of PLOS Genetics, we reported that the double-stranded RNA-binding protein, Staufen1, functions as a disease modifier in the neuromuscular disorder Myotonic Dystrophy Type I (DM1). In this work, we demonstrated that Staufen1 regulates the alternative splicing of exon 11 of the human Insulin Receptor, a highly studied missplicing event in DM1, through Alu elements located in an intronic region. Furthermore, we found that Staufen1 overexpression regulates numerous alternative splicing events, potentially resulting in both positive and negative effects in DM1. Here, we discuss our major findings and speculate on the details of the mechanisms by which Staufen1 could regulate alternative splicing, in both normal and DM1 conditions. Finally, we highlight the importance of disease modifiers, such as Staufen1, in the DM1 pathology in order to understand the complex disease phenotype and for future development of new therapeutic strategies.
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Affiliation(s)
- Emma Bondy-Chorney
- Department of Cellular and Molecular Medicine, University of Ottawa, Center for Neuromuscular Disease , Ottawa, Ontario, Canada
| | - Tara E Crawford Parks
- Department of Cellular and Molecular Medicine, University of Ottawa, Center for Neuromuscular Disease , Ottawa, Ontario, Canada
| | - Aymeric Ravel-Chapuis
- Department of Cellular and Molecular Medicine, University of Ottawa, Center for Neuromuscular Disease , Ottawa, Ontario, Canada
| | - Bernard J Jasmin
- Department of Cellular and Molecular Medicine, University of Ottawa, Center for Neuromuscular Disease , Ottawa, Ontario, Canada
| | - Jocelyn Côté
- Department of Cellular and Molecular Medicine, University of Ottawa, Center for Neuromuscular Disease , Ottawa, Ontario, Canada
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Dash S, Siddam AD, Barnum CE, Janga SC, Lachke SA. RNA-binding proteins in eye development and disease: implication of conserved RNA granule components. WILEY INTERDISCIPLINARY REVIEWS-RNA 2016; 7:527-57. [PMID: 27133484 DOI: 10.1002/wrna.1355] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Accepted: 03/21/2016] [Indexed: 01/16/2023]
Abstract
The molecular biology of metazoan eye development is an area of intense investigation. These efforts have led to the surprising recognition that although insect and vertebrate eyes have dramatically different structures, the orthologs or family members of several conserved transcription and signaling regulators such as Pax6, Six3, Prox1, and Bmp4 are commonly required for their development. In contrast, our understanding of posttranscriptional regulation in eye development and disease, particularly regarding the function of RNA-binding proteins (RBPs), is limited. We examine the present knowledge of RBPs in eye development in the insect model Drosophila as well as several vertebrate models such as fish, frog, chicken, and mouse. Interestingly, of the 42 RBPs that have been investigated for their expression or function in vertebrate eye development, 24 (~60%) are recognized in eukaryotic cells as components of RNA granules such as processing bodies, stress granules, or other specialized ribonucleoprotein (RNP) complexes. We discuss the distinct developmental and cellular events that may necessitate potential RBP/RNA granule-associated RNA regulon models to facilitate posttranscriptional control of gene expression in eye morphogenesis. In support of these hypotheses, three RBPs and RNP/RNA granule components Tdrd7, Caprin2, and Stau2 are linked to ocular developmental defects such as congenital cataract, Peters anomaly, and microphthalmia in human patients or animal models. We conclude by discussing the utility of interdisciplinary approaches such as the bioinformatics tool iSyTE (integrated Systems Tool for Eye gene discovery) to prioritize RBPs for deriving posttranscriptional regulatory networks in eye development and disease. WIREs RNA 2016, 7:527-557. doi: 10.1002/wrna.1355 For further resources related to this article, please visit the WIREs website.
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Affiliation(s)
- Soma Dash
- Department of Biological Sciences, University of Delaware, Newark, DE, USA
| | - Archana D Siddam
- Department of Biological Sciences, University of Delaware, Newark, DE, USA
| | - Carrie E Barnum
- Department of Biological Sciences, University of Delaware, Newark, DE, USA
| | - Sarath Chandra Janga
- Department of Biohealth Informatics, School of Informatics and Computing, Indiana University & Purdue University Indianapolis, Indianapolis, IN, USA.,Center for Computational Biology and Bioinformatics, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Salil A Lachke
- Department of Biological Sciences, University of Delaware, Newark, DE, USA.,Center for Bioinformatics and Computational Biology, University of Delaware, Newark, DE, USA
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Bargiela A, Cerro-Herreros E, Fernandez-Costa JM, Vilchez JJ, Llamusi B, Artero R. Increased autophagy and apoptosis contribute to muscle atrophy in a myotonic dystrophy type 1 Drosophila model. Dis Model Mech 2016; 8:679-90. [PMID: 26092529 PMCID: PMC4486854 DOI: 10.1242/dmm.018127] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Muscle mass wasting is one of the most debilitating symptoms of myotonic dystrophy type 1 (DM1) disease, ultimately leading to immobility, respiratory defects, dysarthria, dysphagia and death in advanced stages of the disease. In order to study the molecular mechanisms leading to the degenerative loss of adult muscle tissue in DM1, we generated an inducible Drosophila model of expanded CTG trinucleotide repeat toxicity that resembles an adult-onset form of the disease. Heat-shock induced expression of 480 CUG repeats in adult flies resulted in a reduction in the area of the indirect flight muscles. In these model flies, reduction of muscle area was concomitant with increased apoptosis and autophagy. Inhibition of apoptosis or autophagy mediated by the overexpression of DIAP1, mTOR (also known as Tor) or muscleblind, or by RNA interference (RNAi)-mediated silencing of autophagy regulatory genes, achieved a rescue of the muscle-loss phenotype. In fact, mTOR overexpression rescued muscle size to a size comparable to that in control flies. These results were validated in skeletal muscle biopsies from DM1 patients in which we found downregulated autophagy and apoptosis repressor genes, and also in DM1 myoblasts where we found increased autophagy. These findings provide new insights into the signaling pathways involved in DM1 disease pathogenesis.
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Affiliation(s)
- Ariadna Bargiela
- Translational Genomics Group, Department of Genetics, University of Valencia, Burjassot 46100, Spain INCLIVA Health Research Institute, Valencia 46010, Spain
| | - Estefanía Cerro-Herreros
- Translational Genomics Group, Department of Genetics, University of Valencia, Burjassot 46100, Spain INCLIVA Health Research Institute, Valencia 46010, Spain
| | - Juan M Fernandez-Costa
- Translational Genomics Group, Department of Genetics, University of Valencia, Burjassot 46100, Spain
| | - Juan J Vilchez
- Neurology Section, Hospital Universitari La Fe, Valencia 46026, Spain Department of Internal Medicine, University of Valencia, Valencia 46010, Spain Centro de Investigaciones Biomedicas en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Institute Carlos III, Ministry of Economy and Competitiveness, Madrid 28049, Spain
| | | | - Ruben Artero
- Translational Genomics Group, Department of Genetics, University of Valencia, Burjassot 46100, Spain INCLIVA Health Research Institute, Valencia 46010, Spain
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25
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Roles for RNA-binding proteins in development and disease. Brain Res 2016; 1647:1-8. [PMID: 26972534 DOI: 10.1016/j.brainres.2016.02.050] [Citation(s) in RCA: 113] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Revised: 02/24/2016] [Accepted: 02/25/2016] [Indexed: 12/13/2022]
Abstract
RNA-binding protein activities are highly regulated through protein levels, intracellular localization, and post-translation modifications. During development, mRNA processing of specific gene sets is regulated through manipulation of functional RNA-binding protein activities. The impact of altered RNA-binding protein activities also affects human diseases in which there are either a gain-of-function or loss-of-function causes pathogenesis. We will discuss RNA-binding proteins and their normal developmental RNA metabolism and contrast how their function is disrupted in disease. This article is part of a Special Issue entitled SI:RNA Metabolism in Disease.
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26
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Bondy-Chorney E, Crawford Parks TE, Ravel-Chapuis A, Klinck R, Rocheleau L, Pelchat M, Chabot B, Jasmin BJ, Côté J. Staufen1 Regulates Multiple Alternative Splicing Events either Positively or Negatively in DM1 Indicating Its Role as a Disease Modifier. PLoS Genet 2016; 12:e1005827. [PMID: 26824521 PMCID: PMC4733145 DOI: 10.1371/journal.pgen.1005827] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Accepted: 01/05/2016] [Indexed: 01/10/2023] Open
Abstract
Myotonic dystrophy type 1 (DM1) is a neuromuscular disorder caused by an expansion of CUG repeats in the 3' UTR of the DMPK gene. The CUG repeats form aggregates of mutant mRNA, which cause misregulation and/or sequestration of RNA-binding proteins, causing aberrant alternative splicing in cells. Previously, we showed that the multi-functional RNA-binding protein Staufen1 (Stau1) was increased in skeletal muscle of DM1 mouse models and patients. We also showed that Stau1 rescues the alternative splicing profile of pre-mRNAs, e.g. the INSR and CLC1, known to be aberrantly spliced in DM1. In order to explore further the potential of Stau1 as a therapeutic target for DM1, we first investigated the mechanism by which Stau1 regulates pre-mRNA alternative splicing. We report here that Stau1 regulates the alternative splicing of exon 11 of the human INSR via binding to Alu elements located in intron 10. Additionally, using a high-throughput RT-PCR screen, we have identified numerous Stau1-regulated alternative splicing events in both WT and DM1 myoblasts. A number of these aberrant ASEs in DM1, including INSR exon 11, are rescued by overexpression of Stau1. However, we find other ASEs in DM1 cells, where overexpression of Stau1 shifts the splicing patterns away from WT conditions. Moreover, we uncovered that Stau1-regulated ASEs harbour Alu elements in intronic regions flanking the alternative exon more than non-Stau1 targets. Taken together, these data highlight the broad impact of Stau1 as a splicing regulator and suggest that Stau1 may act as a disease modifier in DM1.
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Affiliation(s)
- Emma Bondy-Chorney
- Department of Cellular and Molecular Medicine, University of Ottawa; Centre for Neuromuscular Disease, Ottawa, Ontario, Canada
| | - Tara E. Crawford Parks
- Department of Cellular and Molecular Medicine, University of Ottawa; Centre for Neuromuscular Disease, Ottawa, Ontario, Canada
| | - Aymeric Ravel-Chapuis
- Department of Cellular and Molecular Medicine, University of Ottawa; Centre for Neuromuscular Disease, Ottawa, Ontario, Canada
| | - Roscoe Klinck
- Département de microbiologie et d'infectiologie, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Lynda Rocheleau
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario, Canada
| | - Martin Pelchat
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario, Canada
| | - Benoit Chabot
- Département de microbiologie et d'infectiologie, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Bernard J. Jasmin
- Department of Cellular and Molecular Medicine, University of Ottawa; Centre for Neuromuscular Disease, Ottawa, Ontario, Canada
| | - Jocelyn Côté
- Department of Cellular and Molecular Medicine, University of Ottawa; Centre for Neuromuscular Disease, Ottawa, Ontario, Canada
- * E-mail:
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27
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Abstract
RNAi technologies enable the testing of gene function in a cell-type- and stage-specific manner in Drosophila. The development of genome-wide RNAi libraries has allowed expansion of this approach to the genome scale and supports identification of most genes required for a given process in a cell type of choice. However, a large-scale RNAi approach also harbors many potential pitfalls that can complicate interpretation of the results. Here, we summarize published screens and provide a guide on how to optimally plan and perform a large-scale, in vivo RNAi screen. We highlight the importance of assay design and give suggestions on how to optimize the assay conditions by testing positive and negative control genes. These genes are used to estimate false-negative and false-positive rates of the screen data. We discuss the planning and logistics of a large-scale screen in detail and suggest bioinformatics platforms to identify and select gene groups of interest for secondary assays. Finally, we review various options to confirm RNAi knock-down specificity and thus identify high confidence genes for more detailed case-by-case studies in the future.
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28
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Chakraborty M, Selma-Soriano E, Magny E, Couso JP, Pérez-Alonso M, Charlet-Berguerand N, Artero R, Llamusi B. Pentamidine rescues contractility and rhythmicity in a Drosophila model of myotonic dystrophy heart dysfunction. Dis Model Mech 2015; 8:1569-78. [PMID: 26515653 PMCID: PMC4728315 DOI: 10.1242/dmm.021428] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2015] [Accepted: 10/19/2015] [Indexed: 02/01/2023] Open
Abstract
Up to 80% of individuals with myotonic dystrophy type 1 (DM1) will develop cardiac abnormalities at some point during the progression of their disease, the most common of which is heart blockage of varying degrees. Such blockage is characterized by conduction defects and supraventricular and ventricular tachycardia, and carries a high risk of sudden cardiac death. Despite its importance, very few animal model studies have focused on the heart dysfunction in DM1. Here, we describe the characterization of the heart phenotype in a Drosophila model expressing pure expanded CUG repeats under the control of the cardiomyocyte-specific driver GMH5-Gal4. Morphologically, expression of 250 CUG repeats caused abnormalities in the parallel alignment of the spiral myofibrils in dissected fly hearts, as revealed by phalloidin staining. Moreover, combined immunofluorescence and in situ hybridization of Muscleblind and CUG repeats, respectively, confirmed detectable ribonuclear foci and Muscleblind sequestration, characteristic features of DM1, exclusively in flies expressing the expanded CTG repeats. Similarly to what has been reported in humans with DM1, heart-specific expression of toxic RNA resulted in reduced survival, increased arrhythmia, altered diastolic and systolic function, reduced heart tube diameters and reduced contractility in the model flies. As a proof of concept that the fly heart model can be used for in vivo testing of promising therapeutic compounds, we fed flies with pentamidine, a compound previously described to improve DM1 phenotypes. Pentamidine not only released Muscleblind from the CUG RNA repeats and reduced ribonuclear formation in the Drosophila heart, but also rescued heart arrhythmicity and contractility, and improved fly survival in animals expressing 250 CUG repeats.
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Affiliation(s)
- Mouli Chakraborty
- Translational Genomics Group, Incliva Health Research Institute, Avda. Menendez Pelayo 4 acc 46010, Valencia, Spain Department of Genetics and Estructura de Recerca Interdisciplinar en Biotecnologia i Biomedicina (ERI BIOTECMED), Universitat de València, Dr Moliner 50, Burjasot 46100, Spain
| | - Estela Selma-Soriano
- Department of Genetics and Estructura de Recerca Interdisciplinar en Biotecnologia i Biomedicina (ERI BIOTECMED), Universitat de València, Dr Moliner 50, Burjasot 46100, Spain
| | - Emile Magny
- School of Life Sciences, University of Sussex, Falmer, Brighton, East Sussex, BN1 9QG, UK
| | - Juan Pablo Couso
- School of Life Sciences, University of Sussex, Falmer, Brighton, East Sussex, BN1 9QG, UK
| | - Manuel Pérez-Alonso
- Translational Genomics Group, Incliva Health Research Institute, Avda. Menendez Pelayo 4 acc 46010, Valencia, Spain Department of Genetics and Estructura de Recerca Interdisciplinar en Biotecnologia i Biomedicina (ERI BIOTECMED), Universitat de València, Dr Moliner 50, Burjasot 46100, Spain
| | - Nicolas Charlet-Berguerand
- Translational Medicine and Neurogenetics, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), 1 Rue Laurent Fries, 67400 Illkirch-Graffenstaden, France
| | - Ruben Artero
- Translational Genomics Group, Incliva Health Research Institute, Avda. Menendez Pelayo 4 acc 46010, Valencia, Spain Department of Genetics and Estructura de Recerca Interdisciplinar en Biotecnologia i Biomedicina (ERI BIOTECMED), Universitat de València, Dr Moliner 50, Burjasot 46100, Spain
| | - Beatriz Llamusi
- Translational Genomics Group, Incliva Health Research Institute, Avda. Menendez Pelayo 4 acc 46010, Valencia, Spain Department of Genetics and Estructura de Recerca Interdisciplinar en Biotecnologia i Biomedicina (ERI BIOTECMED), Universitat de València, Dr Moliner 50, Burjasot 46100, Spain
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29
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Emerging roles for hnRNPs in post-transcriptional regulation: what can we learn from flies? Chromosoma 2014; 123:515-27. [PMID: 24913828 DOI: 10.1007/s00412-014-0470-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2014] [Revised: 05/21/2014] [Accepted: 05/23/2014] [Indexed: 12/13/2022]
Abstract
Heterogeneous nuclear ribonucleoproteins (hnRNPs) are a highly conserved family of RNA-binding proteins able to associate with nascent RNAs in order to support their localization, maturation and translation. Research over this last decade has remarked the importance of gene regulatory processes at post-transcriptional level, highlighting the emerging roles of hnRNPs in several essential biological events. Indeed, hnRNPs are key factors in regulating gene expression, thus, having a number of roles in many biological pathways. Moreover, failure of the activities catalysed by hnRNPs affects various biological processes and may underlie several human diseases including cancer, diabetes and neurodegenerative syndromes. In this review, we summarize some of hnRNPs' roles in the model organism Drosophila melanogaster, particularly focusing on their participation in all aspects of post-transcriptional regulation as well as their conserved role and involvement in the aetiology of human pathologies.
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30
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In Vivo RNAi-Based Screens: Studies in Model Organisms. Genes (Basel) 2013; 4:646-65. [PMID: 24705267 PMCID: PMC3927573 DOI: 10.3390/genes4040646] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2013] [Revised: 10/29/2013] [Accepted: 11/14/2013] [Indexed: 11/23/2022] Open
Abstract
RNA interference (RNAi) is a technique widely used for gene silencing in organisms and cultured cells, and depends on sequence homology between double-stranded RNA (dsRNA) and target mRNA molecules. Numerous cell-based genome-wide screens have successfully identified novel genes involved in various biological processes, including signal transduction, cell viability/death, and cell morphology. However, cell-based screens cannot address cellular processes such as development, behavior, and immunity. Drosophila and Caenorhabditis elegans are two model organisms whose whole bodies and individual body parts have been subjected to RNAi-based genome-wide screening. Moreover, Drosophila RNAi allows the manipulation of gene function in a spatiotemporal manner when it is implemented using the Gal4/UAS system. Using this inducible RNAi technique, various large-scale screens have been performed in Drosophila, demonstrating that the method is straightforward and valuable. However, accumulated results reveal that the results of RNAi-based screens have relatively high levels of error, such as false positives and negatives. Here, we review in vivo RNAi screens in Drosophila and the methods that could be used to remove ambiguity from screening results.
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31
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Abstract
Skeletal muscle undergoes marked functional decay during aging in humans, but the cell biological mechanisms responsible for this process are only partly known. Age-related muscle dysfunction is also a feature of aging in the fruit fly Drosophila melanogaster. Here we describe a detailed step-by-step protocol, which takes place over 3 d, for whole-mount immunostaining of Drosophila flight muscle. The skeletal muscle is fixed and permeabilized without any tissue freezing and dehydration so that antigens are accessible for staining with appropriate antibodies and the overall tissue ultrastructure is well preserved. This technique can be used to identify age-related cellular changes driving skeletal muscle aging and for characterizing models of human muscle disease in Drosophila.
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Affiliation(s)
- Liam C Hunt
- Department of Developmental Neurobiology, Division of Developmental Biology, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
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32
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Lenz S, Karsten P, Schulz JB, Voigt A. Drosophila as a screening tool to study human neurodegenerative diseases. J Neurochem 2013; 127:453-60. [PMID: 24028575 DOI: 10.1111/jnc.12446] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2013] [Revised: 08/22/2013] [Accepted: 09/03/2013] [Indexed: 11/28/2022]
Abstract
In an aging society, research involving neurodegenerative disorders is of paramount importance. Over the past few years, research on Alzheimer's and Parkinson's diseases has made tremendous progress. Experimental studies, however, rely mostly on transgenic animal models, preferentially using mice. Although experiments on mice have enormous advantages, they also have some inherent limitations, some of which can be overcome by the use of Drosophila melanogaster as an experimental animal. Among the major advantages of using the fly is its small genome, which can also be modified very easily. The fact that its genome lends itself to diverse alterations (e. g. mutagenesis, transposons) has made the fly a useful organism to perform large-scale and genome-wide screening approaches. This has opened up an entirely new field of experimental research aiming to elucidate genetic interactions and screen for modifiers of disease processes in vivo. Here, we provide a brief overview of how flies can be used to analyze molecular mechanisms underlying human neurodegenerative diseases.
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Affiliation(s)
- Sarah Lenz
- Department of Neurology, University Medical Center, RWTH Aachen, Aachen, Germany
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33
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Sicot G, Gomes-Pereira M. RNA toxicity in human disease and animal models: from the uncovering of a new mechanism to the development of promising therapies. Biochim Biophys Acta Mol Basis Dis 2013; 1832:1390-409. [PMID: 23500957 DOI: 10.1016/j.bbadis.2013.03.002] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2012] [Revised: 03/01/2013] [Accepted: 03/04/2013] [Indexed: 01/06/2023]
Abstract
Mutant ribonucleic acid (RNA) molecules can be toxic to the cell, causing human disease through trans-acting dominant mechanisms. RNA toxicity was first described in myotonic dystrophy type 1, a multisystemic disorder caused by the abnormal expansion of a non-coding trinucleotide repeat sequence. The development of multiple and complementary animal models of disease has greatly contributed to clarifying the complex disease pathways mediated by toxic RNA molecules. RNA toxicity is not limited to myotonic dystrophy and spreads to an increasing number of human conditions, which share some unifying pathogenic events mediated by toxic RNA accumulation and disruption of RNA-binding proteins. The remarkable progress in the dissection of disease pathobiology resulted in the rational design of molecular therapies, which have been successfully tested in animal models. Toxic RNA diseases, and in particular myotonic dystrophy, clearly illustrate the critical contribution of animal models of disease in translational research: from gene mutation to disease mechanisms, and ultimately to therapy development. This article is part of a Special Issue entitled: Animal Models of Disease.
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34
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Fernandez-Costa JM, Garcia-Lopez A, Zuñiga S, Fernandez-Pedrosa V, Felipo-Benavent A, Mata M, Jaka O, Aiastui A, Hernandez-Torres F, Aguado B, Perez-Alonso M, Vilchez JJ, Lopez de Munain A, Artero RD. Expanded CTG repeats trigger miRNA alterations in Drosophila that are conserved in myotonic dystrophy type 1 patients. Hum Mol Genet 2012; 22:704-16. [PMID: 23139243 DOI: 10.1093/hmg/dds478] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Myotonic dystrophy type 1 (DM1) is caused by the expansion of CTG repeats in the 3' untranslated region of the DMPK gene. Several missplicing events and transcriptional alterations have been described in DM1 patients. A large number of these defects have been reproduced in animal models expressing CTG repeats alone. Recent studies have also reported miRNA dysregulation in DM1 patients. In this work, a Drosophila model was used to investigate miRNA transcriptome alterations in the muscle, specifically triggered by CTG expansions. Twenty miRNAs were differentially expressed in CTG-expressing flies. Of these, 19 were down-regulated, whereas 1 was up-regulated. This trend was confirmed for those miRNAs conserved between Drosophila and humans (miR-1, miR-7 and miR-10) in muscle biopsies from DM1 patients. Consistently, at least seven target transcripts of these miRNAs were up-regulated in DM1 skeletal muscles. The mechanisms involved in dysregulation of miR-7 included a reduction of its primary precursor both in CTG-expressing flies and in DM1 patients. Additionally, a regulatory role for Muscleblind (Mbl) was also suggested for miR-1 and miR-7, as these miRNAs were down-regulated in flies where Mbl had been silenced. Finally, the physiological relevance of miRNA dysregulation was demonstrated for miR-10, since over-expression of this miRNA in Drosophila extended the lifespan of CTG-expressing flies. Taken together, our results contribute to our understanding of the origin and the role of miRNA alterations in DM1.
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